This invention relates to a film structure for flexible containers. In particular, this invention relates to a multilayer laminate film structure for flexible containers capable of containing a liquid to be maintained under sterile conditions.
Flexible containers are utilized in the medical industry for containing, inter alia, parenteral solutions including intravenous solutions, dialysis solutions, nutrition products, respiratory therapy products, and plasma. Because these containers are utilized to contain fluids or solids that are introduced into a patient's body, it is necessary for the containers to be: essentially transparent; flexible; essentially free of extractables; and capable of maintaining the product contained therein under sterile conditions until the product is accessed or removed from the flexible container.
It is necessary that these containers are highly transparent, with little or no haze, so that the solution contained therein can be observed clearly and easily; this allows one to determine if the solution contained therein is contaminated, denatured, or defective in some other way. In addition, it is also sometimes necessary for the container to have a low water vapor and oxygen permeability so as not to degrade the solution contained therein.
It is also desirable for the container to be sufficiently strong and have a sufficiently high breaking strength so that the container will not be easily damaged if it is accidentally dropped. Moreover, the film from which the container is constructed should have satisfactory heat sealing properties so that the inside layer of the film may be heat sealed together to create the container in some type of production machine. Furthermore, the container should have sufficient heat resistant properties to withstand steam or other high temperature (100.degree.-140.degree. C.) sterilization. This requires that the container does not lose its transparency during sterilization.
Typical containers for medical solutions and the like include glass bottles, blow-molded polypropylene containers, and polyvinyl chloride bags. Each of these containers exhibit some potential disadvantage.
Glass bottles are easily broken. Moreover, the alkali ingredients in the glass may be leached out into the solution. Furthermore, glass bottles, because they do not collapse, must be vented. It is possible for infection to be transmitted to the patient due to the venting. Of course, glass does not provide a container that is flexible.
Blow-molded polypropylene containers lack needed transparency. Like glass bottles they also must be vented and accordingly there is the possibility of infection due to this venting.
In polyvinyl chloride bags it is possible that the plasticizers in the film may leach out into the solution.
Thus, there is a need for a film for creating a flexible container that overcomes the disadvantages of the prior art.